My husband I got chicks and then promptly had a bunch of family emergencies so the coop was finished late and then there was not run. Anyway we are now looking to finish quickly so all our plans for cheap recycled stuff went out the window. This weekend we were trying to add a pop door and he was talking about grooving wood and blah, blah. As we were at Lowe's we noticed a bathroom window is about the perfect size for a pop door. We cut a hole in the coop. Screwed it to the outside, removed the screen. Whala! Pop door that can be closed, locked and somewhat weather tight. The latches that lock it just get pushed in against a spring, so later if I don't want to lock it every night he's just going to drill a small hole in the each latch and tie them together with picture hanger wire so the locks stay open til we want them closed. The window cost was $54. Wood definately cheaper but it looks nice and was super easy.